Utility stool



D. H. HALE UTILITY STOOL Sept. 8, ,1964

2 Sheets-Sheet 1 Filed Oct. 13, 1961 INVENTOR.

DEAN H. HALE ATTORNEYS p 3, 1964 D. H. HALE 3,147,946

UTILITY STOOL Filed Oct. 13, 1961 2 Sheets-sheet 2 F/G. 6. F/G. Z

DEAN H. HALE.

ATTORNEYS United States Patent C) 3,147,946 UTILITY STGOL Dean H. Hale, Logan, Utah, assignor to Vacudent Manufacturing Company, Sait Lake City, Utah, a corporation of Utah Filed Oct. 13, 1961, Ser. No. 144,980 4 Claims. (Cl. 248- 504) This invention relates to seating structures, and particularly to stools for special purposes.

The invention is concerned primarily with providing a stool for dentists and dental assistants to be used while working on or administering to dental patients seated in a dental operating chair, although many other uses are possible. The invention is closely related to that set forth in the application for patent concurrently filed herewith by Elbert 0. Thompson and me jointly entitled Stool for Dentists.

Dentists and dental assistants normally stand while working on or administering to a patient in the dental chair. However, the necessity of bending over and peering into the mouth of the patient imposes considerable strain on the body and results in fatigue and often in muscular pains of one kind or another.

While seating of the dentist during his work has been proposed heretofore and stools have been provided for this purpose, the needs of a dentist and a dental assistant are such that stools of ordinary construction encumber more than they aid.

Principal objects of the present invention were to provide unique foot-pedal-operated, self-powered mechanism for enabling the user to raise the seat without removing his eyes or hands from the work in progress and so that no utility lines need extend to the seating structure and no manual pumping nor other input of energy is required; and to provide a unique cam lock for easily and positively locking adjustable components in their adjusted positions.

Outstanding features of the invention with respect to the self-powered mechanism are provision for hydraulic actuation of extendible and retractable, piston and cyl; inder, seat-supporting structure by means of compressed air trapped in the hydraulic fluid reservoir, so that the seat will rise by merely opening a valve controlling flow of hydraulic fluid between reservoir and cylinder; provision for slowly bleeding the hydraulic fluid out of the cylinder;

and back into the reservoir; and separation of the piston transversely into two parts, so the seat can be raised independently of the power system, without damaging the seal between piston and cylinder.

Outstanding features of the invention with respect to the cam lock are the provision of a lever-actuated, cam rod journaled in a receptacle, transversely of a throughway therethrough which receives a bar to be locked. The cam rod is cylindrical except for a flat sector terminating in a protruding lip and terminal wall which limits throw of the cam rod and protects against over-ride from locking position.

A specific embodiment of the invention representing what is presently regarded as the best mode of carrying out the inventive concepts in actual practice is illustrated in the accompanying drawings.

In the drawings:

FIG. 1 represents an elevational view of a dental stool looking directly toward the back of the post which supports the body rest;

FIG. 2, a top plan view, with a different adjustment of the body rest being indicated by broken lines;

FIG. 3, a bottom plan view;

FIG. 4, a fragmentary view in vertical section taken on the line 44 of FIG. 1 and drawn to a larger scale, showing one of the cam locks in its locked position;

FIG. 5, a corresponding view, but showing the cam lock in its unlocked position;

FIG. 6, a fragmentary view in vertical section taken on the line 66 of FIG. 3 and drawn to a considerably larger scale, the power mechanism being shown in detail but certain intermediate portions of the stool structure being broken away for convenience of illustration; and

FIG. 7, a corresponding view with the seat extended to its maximum height, the seat and part of its supporting post being broken away for convenience of illustration.

Referring to the drawings:

In the form illustrated, the stool comprises a circular seat 10 supported in stool fashion at the upper end of a post 11, which depends centrally from the seat into a receiving tube 12. Post 11 and tube 12 together forming a multi-section, extendible and retractable, fluid-pressure cylinder assembly mounted in a base 13, tube 12 being fixed therein as by welding.

Base 13 is platform-like and hollow, being maneuverably supported by castors 14. There must be at least three castors for stability, as is quite apparent, but in accordance with one aspect of the invention there are five, so that, regardless of floor uneveness, there will always be at least a three-point support for the stool with consequent stability at all times during use. The platform character of this base, coupled with the fact that its diameter significantly exceeds that of the seat 10, enables a person seated on such seat to comfortably and effectively rest his or her feet oif the floor when found desirable.

For added strength and to facilitate lubrication, a sleeve 15 is secured to the upper end of tube 12 and extends down to the base 13 as a tube housing, where it is secured as by welding. A ring of oil-impregnated felt 16 wipes oil onto the surface of post 11 as it rises and descends relative thereto.

In order to provide support for the trunk of the body of a dentist or dental assistant when working from a seated position and leaning outwardly from the seat 10, an abdominal rest .17 is provided in upwardly spaced relationship with the seat. It is supported in what is essentially cantilever fashion from a post 18, which is preferably a broad and rigid bar or strip of some such material as steel or aluminum rising above the seat near the circumference thereof.

Body rest 17 is of broad strip formation in the sense that it is wide but relatively elongate, so as to provide comfortable and effective support for the body at or near the waist. It and seat 10 are preferably cushioned with foam rubber or the like and upholstered with a washable plastic sheet material.

While in some instances it may be desirable to construct the stool with the body rest permanently fixed to its supporting post, in the illustrated construction rest 17 is adjustably positioned relative to post 18 so as to accommodate thin as well as stout persons. In any event, the rest is largely curved in conformity with the seat and is positioned so that its width extends vertically and so that its length extends horizontally in cantilever fashion from one side of the post.

To enable a person to easily move into and out of position on the seat with respect to the body rest, such body rest preferably has its opposite end portions deviating outwardly from the aforespecified curvature, the end portion 17a nearest the supporting post 18 advantageously being rectilinear or approximately so. Best results are had when the circularly curved intermediate portion of the rest subtends an angle of about For the purpose of adjustment, rest 17 is provided with a bracket arm 19, which extends from near the middle of such rest backwardly and outwardly along the back of one end portion of the rest, see particularly FIG. 2, and is firmly secured to post 18 by suitable releasable fasten- 3 ing means, such as a unique cam lock 20 operable by hand lever 21 and constructed as shown in detail in FIGS. 4 and 5. In turn, post 18 is firmly but adjustably secured to the rest of the stool structure by means of a second cam lock 22, FIG. 1, operable by hand lever 23.

While cam lock 22 is illustrated in FIGS. 4 and S, cam lock 20 is of the same type. As shown, a slotted receptacle 24, FIGS. 4 and 5, defines a throughway for slidably receiving post 18 (bracket arm 19 in the instance of cam lock 20). Extending across the interior of receptacle 24 and journaled in the lateral Walls thereof is a cam 25 in the form of a rod whose cross section is circular, except for a sector face 26 which is preferably provided with a continuation in the form of a protuberant lip 27 having a terminal face 27a at substantially right angles thereto merging into the otherwise cylindrical periphery of the rod along a tangent. It is a feature of the invention that cam rod 25 is of a self-lubricating, plastic material such as rigid polyethylene.

The lever arm or operating handle 23 (21 in the instance of cam lock 20) is fixed to one end of the cam rod 25 perpendicularly to the sector face 26 of such rod, so that, when such handle is turned up as shown in FIG. 1 (inwardly in the instance of handle 21 of cam lock 20) a curved portion of such rod exercises cam action against the opposing face of post 18 to frictionally lock it tightly against opposing face portions of receptacle 24.

When it is desired to adjust the height of body rest 17 and post 13 relative to seat 10, it is only necessary to throw handle 23 downwardly and outwardly to bring sector face 26 into parallel position with the aforesaid opposing face of post 13, see FIG. 5. Lip 27 prevents over-ride and positively establishes the unlocked position. Likewise with cam lock 20, it is only necessary to turn handle 21 clockwise to a position substantially perpendicular to bracket arm 19 in order to permit positional adjustment of body rest 17 relative to its supporting post 18 and to seat 10.

Receptacle 24 of cam lock 22 is secured, as by welding, to the outer and upwardly turned end of a mounting bar 28, so that its throughway is disposed vertically for slidably receiving post 18, while the receptacle of cam lock 20 is similarly secured to the upper end of post 18 with its throughway disposed horizontally for slidably receiving bracket arm 19.

Mounting bar 28 is secured, as by welding, to the upper end of post 11, and, in order to provide for independent swiveling movement of seat and body rest 17 relative to each other, an anti-friction bearing 29, FIG. 6, has its upper race plate 29a secured to the seat, as by bolts 30, and its lower race plate 2% secured to mounting bar 28 and post 11, as by welding.

The self-contained power mechanism for raising seat 10, and coincidentally body rest 17, is housed within hollow base 13 and is operated by a foot pedal 31 which projects a convenient distance beyond the outer periphery of the base, see FIGS. 1, 2 and 3, at a location that is preferably diametrically opposite one of the castors 14. In order that the person seated on the stool can easily locate such foot-pedal without looking down, it is preferred to permanently fix such opposite castor against swiveling movement, as by driving a pin (not shown) through the castor shank and its holder.

The power mechanism shown is of hydraulic type and utilizes captive air under pressure to force a non-compressible hydraulic fluid, such as oil, into the lower end of tube 12.

A reservoir 32 for the pressure air and hydraulic fluid communicates with the lower end of tube or cylinder 12 by means of a conduit 33, in which is interposed a normally closed valve 34 of standard type having a spring-loaded valve member 35 operated by a lever 36 secured to the inner end of foot-pedal 31 for controlling flow of the pressurized hydraulic fluid to and from tube 12.

Conduit 33 is directly connected to a check valve body 4 37, which is secured to the lower end of tube 12 and contains a seat 38 for a ball check 39 above a through passage 40. Conduit 33 leads into one end of passage 40, and an air-injection fitting 41 leads into the opposite end. Fitting 41 is equipped with a standard air-injection valve (not shown) similar to those used for pneumatic tires, whereby compressed air can be introduced from an ordinary air hose for initially charging reservoir 32 to a pressure of from about 60 to p.s.i. and for repressurizing if and when necessary.

Inasmuch as tube 12 and check valve body 37 depend deeply into base 13, braces 42, extending and secured to the underside of base 13, are provided for strength and stability.

Seat-supporting post or piston 11 fits tube 12 snugly along a lower end portion 11a, but is of reduced diameter above to provide a shoulder 11b which serves as an abutment stop when it reaches cap 151 of sleeve 15 in the upward adjustment of seat height.

Post 11 is preferably made with its lowest portion as a separate part 111, to which is attached a cup seal 43. In this way, seat 10 and its post 11 are free to be moved upwardly independently of seal 43, and there is no possibility of damaging such seal by forced raising of the seat, apart from power actuation, as would be the case were the post not made up of separate parts. Such parts are preferably abruptly tapered where they meet, as shown at 11-2, to provide a relief area.

The height of stool seat 10 is adjusted by pressing footpedal 31. It is not intended that there be a lifting of a person seated on the stool, but, rather, that there be a powered lifting of the stool seat 10 alone, since this is all that is necessary from a practical standpoint. Thus, when the dentist or other person using the stool desires to alter his working position upwardly, he need merely step on the foot-pedal while raising his body. The stool seat will closely follow until the pedal is released, whereupon a sitting position can be resumed without ever having taken eyes or hands from the work in progress. It is apparent that opening of pedal valve 34 permits the entrapped compressed air in reservoir 32 to expand and force hydraulic fluid 44, FIG. 7, into tube 12. Subsequent closing of the valve prevents return flow of hydraulic fluid to reservoir 32 when the user sits down and effectively acts as a locking means to maintain the seat fixed at any given position of extension or retraction of its supporting assembly.

Ball check 39 is preferably of steel or other heavy material, so as to seat when post 11 and its auxiliary part 111 are raised as in FIG. 7. Thus, when it is desired to lower the height of stool seat 10 and foot-pedal 31 is pressed for that purpose, the hydraulic fluid 44 is trapped against rapid escape from tube 12 and there is no sudden descent of the seat. Instead, a bleeder passage 45 provides for gradual return of fluid 44 to reservoir 32 and, therewith, a gradual lowering of such seat.

It should be realized that, because the reservoir is pressurized, it will be necessary for the user to rest his or her weight on the stool seat while the foot-pedal is pressed in order to lower such seat from any given height.

Whereas there is here illustrated and described a certain preferred construction which I presently regard as the best mode of carrying out my invention, it should be understood that various changes may be made without departing from the inventive concepts particularly pointed out and distinctly claimed herebelow.

I claim:

1. Pneumatically powered seating structure, comprising a seat; means for supporting the seat, including a support and a hydraulic piston and cylinder interposed between seat and support, with one secured to the seat and one secured to the support; said piston being separated transversely into two independent parts, one of said parts being free of other structure and carrying a seal wiping the cylinder walls, the other of said parts being freely rotatable within the cylinder; a fluid-tight reservoir in fluid-flow communication with the cylinder, for extending piston and cylinder relative to each other; a hydraulic fluid partially filling the reservoir; a compressed fluid trapped within the reservoir and exerting seat-raising pressure on said hydraulic fluid; a control valve normally closing said communication between reservoir and cylinder; and means for opening said valve as and when desired, for raising the seat.

2. Pneumatically powered seating structure, comprising a seat; means for supporting the seat, including a support and a hydraulic piston and cylinder interposed between said seat and support, with one secured to the seat and one secured to the support; said piston being separated transversely into two independent parts, one of said parts being free of other structure and carrying a seal wiping the cylinder walls, the other of said parts being freely rotatable within the cylinder; a fluid-tight reservoir in fluid-flow communication with the cylinder for extending piston and cylinder relative to each other; a hydraulic fluid partially filling the reservoir; a compressed fluid trapped within the reservoir and exerting seat-raising pressure on said hydraulic fluid; and manually operable means for locking said seat in position when said piston and cylinder have been extended relative to each other.

3. The seating structure of claim 1, wherein at least one of the mutually opposing ends of the piston parts is of reduced diameter to provide relief space between said parts.

4. Pneumatically powered seating structure, comprising a seat; means for supporting the seat, including a support and a hydraulic piston and cylinder interposed between seat and support, with one secured to the seat and one secured to the support; said piston being separated transversely into two independent parts, a fluid confining seal abutting one of said parts for preventing flow of hydraulic fluid between said piston parts and said cylinder wall, the other of said parts being freely rotatable within the cylinder; a fluid-tight reservoir in fluid-flow communication with the cylinder, for extending piston and cylinder relative to each other; a hydraulic fluid partially filling the reservoir; a compressed fluid trapped within the reservoir and exerting seat-raising pressure on said hydraulic fluid; a control valve normally closing said communication between reservoir and cylinder; and means for opening said valve as and when desired for raising the seat.

References Cited in the file of this patent UNITED STATES PATENTS 394,224 Stone Dec, 11, 1888 413,156 Wilkerson Oct. 15, 1889 530,880 Briggs Dec. 11, 1894 562,390 Gould June 23, 1896 1,488,206 Koenigkramer Mar. 25, 1924 2,231,631 Maina Feb. 11, 1941 2,446,127 Cramer July 27, 1948 2,542,480 Cramer et al Feb. 20, 1951 2,587,121 Deardorff Feb. 26, 1952 2,590,718 Lundquist Mar. 25, 1952 2,597,332 Janes May 20, 1952 2,692,012 Cramer Oct. 19, 1954 2,698,047 Ralston Dec. 28, 1954 2,778,627 Sands Jan. 22, 1957 FOREIGN PATENTS 1,072,606 France Mar. 17, 1954 

1. PNEUMATICALLY POWERED SEATING STRUCTURE, COMPRISING A SEAT; MEANS FOR SUPPORTING THE SEAT, INCLUDING A SUPPORT AND A HYDRAULIC PISTON AND CYLINDER INTERPOSED BETWEEN SEAT AND SUPPORT, WITH ONE SECURED TO THE SEAT AND ONE SECURED TO THE SUPPORT; SAID PISTON BEING SEPARATED TRANSVERSELY INTO TWO INDEPENDENT PARTS, ONE OF SAID PARTS BEING FREE OF OTHER STRUCTURE AND CARRYING A SEAL WIPING THE CYLINDER WALLS, THE OTHER OF SAID PARTS BEING FREELY ROTATABLE WITHIN THE CYLINDER; A FLUID-TIGHT RESERVOIR IN FLUID-FLOW COMMUNICATION WITH THE CYLINDER, FOR EXTENDING PISTON AND CYLINDER RELATIVE TO EACH OTHER; A HYDRAULIC FLUID PARTIALLY FILLING THE RESERVOIR; A COMPRESSED FLUID TRAPPED WITHIN THE RESERVOIR AND EXERTING SEAT-RAISING PRESSURE ON SAID HYDRAULIC FLUID; A CONTROL VALVE NORMALLY CLOSING SAID COMMUNICATION BETWEEN RESERVOIR AND CYLINDER; AND MEANS FOR OPENING SAID VALVE AS AND WHEN DESIRED, FOR RAISING THE SEAT. 